More specifically, the present invention relates to a coupling comprising a first coupling member made in one piece from composite material and having a first flange portion for attachment to a first drive element, a diaphragm portion that extends radially outwardly from the first flange portion, a second flange portion and a tube portion extending from an outer circumference of the diaphragm portion to the second flange portion, a second coupling member made in one piece from composite material and having a first flange portion for attachment to a second drive element, a diaphragm portion that extends radially outwardly from the first flange portion, a second flange portion and a tube portion extending from an outer circumference of the diaphragm portion to the second flange portion, and connecting elements connecting the first coupling member and the second coupling member at their second flange portions.
Couplings of this type allow for compensation of angular, radial and axial displacements that may occur between the axes of rotation of drive elements of a drive shaft. At least two diaphragms that are spaced apart from each other in axial direction are used for compensating angular and/or larger radial displacements. During rotation of the drive shaft the diaphragm portions of the coupling members deform elastically thereby providing the desired effect. Typical applications of such compensating couplings include drive trains of ships and the like where the coupling is arranged in a drive shaft between an engine and a gearbox. Such applications are characterised by limited axial space. Specifically, it is often impossible or extremely complicated and thus expensive to remove the engine or gearbox or even parts thereof for mounting or dismounting the coupling between them.
U.S. Pat. No. 6,095,924 A discloses a coupling of the type mentioned above addressing these issues. In particular, it is possible to mount the coupling between the drive elements without changing the position of the latter. That is, the coupling can be easily inserted in or removed from an installation space between the engine and the gearbox. During assembly the first coupling member is attached to the first drive element by connecting the first flange portion of the first coupling member to the first drive element. Due to the absence of the second coupling member at that stage the first flange portion can be bolted to a flange of the first drive element from the side of the first coupling member that will later be covered by the second coupling member. Thus, it is possible to arrange the diaphragm portion very close to a structure receiving or supporting the first drive element. Subsequently, the second coupling member is inserted between the first coupling member and the second drive element. Since the first flange of the second element is shielded by the tube portions of the coupling, it can be bolted to a flange of the second drive element only from the rear side of the latter. In order to access the corresponding bolts for mounting and dismounting them sufficient space must be provided between the rear of the flange of the second drive element and a corresponding housing or supporting structure. This reduces the axial distance between the diaphragm portions of the first and second coupling members and thus the possible range for compensating displacements between the axes of rotation of the first and second drive elements.
Another coupling having coupling members made from vulcanized fabric layers is known from U.S. Pat. No. 1,664,052. The coupling members have flexible portions of skeleton or spider form and are connected between drive elements in a conventional manner from the outside so that the distance between the flexible portions remains small.
The present invention aims at improving the compensation potential of the coupling in relation to its axial length without impairing torque transmission or increasing materials usage.